The long-term objectives of this proposal are to define the mechanisms underlying the neurotoxic effects of ethanol in Fetal Alcohol Syndrome (FAS). Deletion of adenylyl cyclases, AC1 and/or ACS,sensitizes developing striatal neurons to death after activity blockade, however, the neuroprotective mechanisms by which these ACs act are unknown. This proposal will test the hypothesis that AC1 or ACS act by unique presynaptic and postsynaptic mechanisms to increase NMDA receptor signaling in the setting of ethanol exposure or activity blockade. We will test this hypothesis with the following Aims: I) define the anatomic relationship of AC1 and ACS to pre- and postsynaptic aspects of striatal synapses undergoing ethanol- induced apoptosis using immunohistochemical and biochemical fractionation techniques; II) determine the sensitivity of striatal neurons to activity blockade by ethanol and NMDA receptor antagonists and identify prosurvival protein targets of AC1 and ACS in vivo using mice with conventional and conditional AC deletion; and III)determine the sensitivity to activity blockade of corticostriatal co-cultures and the molecular mechanisms by which AC1 and ACS modulate this sensitivity. Defining the molecular mechanisms and targets that determine sensitivity or resistance to ethanol neurotoxicity in the striatum and other brain regions is critical to the design of therapies to limit the pathological sequelea associated with FAS. The candidate is currently a postdoctoral fellow whose career goal is to elucidate the mechanisms of ethanol action on neuronal sensitivity, with an emphasis on understanding ethanol-induced neurotoxicity in the developing brain. Mentored scientific training under Dr. Louis Muglia at Washington University provides an ideal setting to do so, allowing the candidate to gain skills needed to become an independent investigator. As a major part of her training, the candidate will develop a novel corticostriatal co-culture system to dissect the roles of AC1/AC8 in vitro, under co-sponsorship of Dr. Karen O'Malley, an expert in the field of dopaminergic signaling and the effects of neurotoxicity. Training in the use of confocal imaging and vital dyes will be provided by Dr. Steve Mennerick. The candidate aims to achieve a faculty position early during this training period and apply for independent funding during the final years of the award. Relevance to Public Health: Perhaps the greatest long-term impact of alcohol use is the effects on the developing fetus, which can result in fetal alcohol syndrome. Though the association of alcohol use during pregnancy and fetal neurotoxicity is clear, mechanisms underlying the pathological consequences in the brain remain undefined, hindering the development of improved therapies. The goal of the proposed research project is to elucidate the molecular mechanisms and targets associated with ethanol-induced neurotoxicity in the developing brain.